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Biomedical subjects

T Toya

Publications and source records attributed to T Toya.

29 records · Page 2Linked to original sources
PubMed1993

MASCOT: multiple alignment system for protein sequences based on three-way dynamic programming.

A multiple alignment methodology that can produce high-quality alignment is extremely important for predicting the structure of unknown proteins. Nearly all the methodologies developed so far have employed two-way alignment only. Although these methods are fast, the alignments they produce lose reliability as the similarity of sequences reduces. We developed the MASCOT multiple alignment system. MASCOT can sustain the reliability of alignment even when the similarity of sequences is low. MASCOT achieves high-quality alignment by employing three-way alignment in addition to two-way alignment. The resultant alignments are refined by simulated annealing to higher quality. We also use a cluster analysis of sequences to produce highly reliable alignments.

Algorithms↗
PubMed1993

Multiple sequence alignment by parallel simulated annealing.

We have developed simulated annealing algorithms to solve the problem of multiple sequence alignment. The algorithm was shown to give the optimal solution as confirmed by the rigorous dynamic programming algorithm for three-sequence alignment. To overcome long execution times for simulated annealing, we utilized a parallel computer. A sequential algorithm, a simple parallel algorithm and the temperature parallel algorithm were tested on a problem. The results were compared with the result obtained by a conventional tree-based algorithm where alignments were merged by two-way dynamic programming. Every annealing algorithm produced a better energy value than the conventional algorithm. The best energy value, which probably represents the optimal solution, was reached within a reasonable time by both of the parallel annealing algorithms. We consider the temperature parallel algorithm of simulated annealing to be the most suitable for finding the optimal multiple sequence alignment because the algorithm does not require any scheduling for optimization. The algorithm is also useful for refining multiple alignments obtained by other heuristic methods.

Algorithms↗
PubMed1993

Carcinogenicity of benzotrichloride administered to mice by gastric intubation.

Epidemiological studies suggest that benzotrichloride (BTC) is a human carcinogen. In the present study, BTC was tested to evaluate its ability to induce lung tumors as a result of systemic exposure. Administration of BTC by gastric intubation, 2.0-0.0315 microliters/mouse (4 doses), twice a week for 25 weeks, in female ICR mice, produced forestomach tumors (squamous cell carcinoma and papilloma), lung tumors (adenocarcinoma and adenoma) and tumors of the hematopoietic system (thymic lymphosarcoma and lymphatic leukemia) with dose-related response by 18 months. The present and previous studies indicate that the target organs of BTC carcinogenesis in mice are the local tissue which is primarily exposed, and the lung and hematopoietic tissue when BTC is administered systematically.

Administration, Oral↗
PubMed1990

Development of an inhalation system of high melting point metal fumes and its use for exposure of rats to chromium and nickel fumes.

An experimental inhalation system was developed for fumes generated from powders of high melting point metals such as chromium, nickel, manganese and iron. The system consisted of a plasma flame metal sprayer as a fume generator, a granular bed type fume collector, a fluidized bed aerosol generator, an exposure and a control chamber of a horizontal-flow type and inhalant monitoring and controlling units. Performance of the chambers was ensured by a distribution test using flyash as a test aerosol. Using this system, rats were exposed to chromium fumes for one week or to nickel fumes for two months. The exposure concentrations of the chromium and nickel fumes were 1.85 +/- 0.55 mg/m3 and 0.51 +/- 0.15 mg/m3 (mean +/- SD), near the target levels of 2 mg/m3 and 0.5 mg/m3, respectively. The mass median aerodynamic diameter and the geometric standard deviation of the chromium fumes were 2.1 microns and 2.00, respectively. Those of the nickel fumes were 3.7 microns and 1.74, respectively. Species analysis of these fume particles revealed that 26.4% of the total chromium was hexavalent and the residue was trivalent and that 1-3% of the total nickel was nickel(III) and the residue was nickel(II). Inhaled-metal concentrations in the lungs showed steady increases with the exposure periods and were within the normal range of variation. On the basis of these results, it is concluded that this system is useful for long-term inhalation experiments using high melting point metal fumes.

Administration, Inhalation↗
PubMed1986

Therapeutic hepatic vein angioplasty for Budd-Chiari syndrome.

The authors report a case of Budd-Chiari syndrome treated by percutaneous transluminal angioplasty (PTA). In this case, the occlusion of three major hepatic veins with a big collateral to the inferior vena cava via the right inferior hepatic vein (RIHV) and stenosis of the ostium of RIHV were seen. We performed successful PTA of this stenosis.

Angioplasty, Balloon↗
PubMed1975

Treatment of hepatocellular carcinoma with adriamycin. Preliminary communication.

In a Phase II clinical trial, 14 patients with histologically proven primary hepatocellular carcinoma were treated with adriamycin administered intravenously at a dose of 75 mg/m2 every 3 weeks. All 11 evaluable patients responded with 3 exhibiting complete tumor regression after two, three, and five courses of adriamycin respectively. The remission durations for these 3 were 3, 6, and 7 months, and their survivals were 8, 9, and 13 months, respectively. The median survival of the evaluable patients is 8 months (range 1-13 months). The side effects encountered included myelosuppression, anorexia, nausea, vomiting, and alopecia. Adriamycin seems to be an effective agent in hepatocellular carcinoma. Further trials are underway to test its true efficacy both singly and in combination with other drugs in the management of this tumor.

Adult↗